The present invention relates to a locator system. More particularly, the present invention relates to a locator system utilizing tags.
Locator systems can be utilized for asset tracking. Generally, a locator system is comprised of a handheld transceiver that facilitates remote location of items attached to or integrated with radio frequency (RF) tags. The handheld transceiver is typically a dedicated unit specifically designed to display data, execute software and provide RF signals that wirelessly poll the RF tags. The handheld transceiver includes a memory to store data received from the RF tags. Dedicated handheld units are expensive because they require a user interface, a power supply, a memory, a processor, and RF circuitry.
The RF tags typically include a transceiver and a memory, such as, an electronically erasable programmable read only memory (EEPROM). The transceiver and EEPROM are powered by a battery. The EEPROM of the RF tags are preprogrammed with a specific address or identification number. The RF tags are affixed to the outside of an item or integrated within the equipment that is to be tracked or located.
To locate an asset, the handheld transceiver provides an interrogation signal. All RF tags within the range of the interrogation signal respond to the interrogation signal and provide a signal containing the identification of the RF tag to the handheld transceiver. In certain conventional systems, the RF tag can also generate a beep in response to the interrogation signal to assist the finding of the equipment within the room or area being searched. The operation of the beep or other audible or visual indications can be controlled through the handheld transceiver.
Heretofore, the locator systems have not been able to precisely locate the asset within an area. Although conventional handheld locator systems provide an indication that the asset is within the range of the interrogation signal, locator systems generally do not provide a more precise indication of the location or even an indication of the direction to the tag from the handheld unit.
In certain conventional systems, the tags can also store a department number, group number or other identification in addition to the tag identification number. The department number can be used to identify a class of asset (e.g., wheelchair, heart monitors, IV pumps, etc.) or a group that is responsible for the asset (cardiology, janitorial, information systems, accounting, etc.). The tag generally provides the department number along with the identification of the RF tag in response to the interrogation signal.
Heretofore, the handheld transceiver has not been able to interrogate an area with limitations on particular department identifications. When the handheld transceiver is utilized in a particular area, all RF tags within range of the interrogation signal respond. The response by all tags within the area unnecessarily adds to the process of acquiring information when a user is only interested in receiving a response from certain RF tags, such as, those tags from a particular department. For example, if a user is interested in only obtaining tags associated with wheelchairs, and not tags associated with other medical equipment, the user has to wait to receive response form all tags before analyzing the responses from tags associated with wheelchairs.
Conventional handheld transceivers have also included a feature which provides the battery power level provided to the handheld computer in response to the interrogation signal. The battery power level is measured by circuitry within the RF tag. However, such systems do not provide day-to-day or more accurate indications of when the battery is expected to expire. The lack of more detailed and more timely information about battery expiration can allow the battery to expire without the user being aware of it. For example, if a tag unit is interrogated only every six months, the battery would likely expire during that six month period and the user would never know low levels of battery life had been reached.
Accordingly, there is a need for a tag unit and locator system that can more accurately determine when battery life in a tag unit will expire. There is also a need for a locator system that automatically provides an indication when the battery life of a tag unit will expire. Further still, there is a need to associate tag units found in a particular area with that particular area. There is also a need for an automated method of associating tag units with a particular area by polling a particular area. There is also a need for a locator system that is capable of selecting only tags associated with a particular department or product for a response to the interrogation signal. There is another need for a locator system that displays radio signal strength values as a bar graph to assist a user in determining the distance to an asset. There is also a need for a handheld transceiver unit that can be implemented using a common handheld computer such as a PALM®, Sony®, or Hewlett Packard® handheld computer (e.g., personal digital systems (PDA's)). Yet further still, there is a need for a low cost, reliable locator system.